It is difficult to make a direct comparison between the present engine and other engines, in order to give the reader some insight into the improvements, because it is our belief that no other engine works on the combination of direct and reflected shock waves. Certain pressure exchanger devices and supercharger devices employ a direct shock wave principle, such a device being the Brown Boveri "Comprex". However, pressures developed in these prior art devices fall considerably below the pressures developed in the present engine. In addition, the Comprex is not an engine in the sense that it does not do any useful work other than compression. In the Comprex, the hot gases are used to produce the final stage of compression, after which the hot gases are used to drive downstream turbines. Neither the Comprex nor its successors utilized rotor chamber nozzles in combination with reflected shock waves to achieve high compression.